PRAZOSIN

Details

Stereochemistry	ACHIRAL
Molecular Formula	C19H21N5O4
Molecular Weight	383.4011
Optical Activity	NONE
Defined Stereocenters	0 / 0
E/Z Centers	0
Charge	0

SHOW SMILES / InChI

Structure Search

SMILES

COC1=CC2=C(C=C1OC)C(N)=NC(=N2)N3CCN(CC3)C(=O)C4=CC=CO4

InChI

InChIKey=IENZQIKPVFGBNW-UHFFFAOYSA-N

InChI=1S/C19H21N5O4/c1-26-15-10-12-13(11-16(15)27-2)21-19(22-17(12)20)24-7-5-23(6-8-24)18(25)14-4-3-9-28-14/h3-4,9-11H,5-8H2,1-2H3,(H2,20,21,22)

HIDE SMILES / InChI

Molecular Formula	C19H21N5O4
Molecular Weight	383.4011
Charge	0
Count

Stereochemistry	ACHIRAL
Additional Stereochemistry	No
Defined Stereocenters	0 / 0
E/Z Centers	0
Optical Activity	NONE

Description
Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2015/017442%20s043lbl.pdf

Prazosin (trade names Minipress, Vasoflex, Lentopres, and Hypovase) is a selective α-1-adrenergic receptor antagonist used to treat hypertension. Prazosin acts by inhibiting the postsynaptic alpha-1-adrenoceptors on vascular smooth muscle. This inhibits the vasoconstrictor effect of circulating and locally released catecholamines (epinephrine and norepinephrine), resulting in peripheral vasodilation. Prazosin is orally active and has a minimal effect on cardiac function due to its alpha-1 receptor selectivity. However, when prazosin is started, heart rate and contractility go up in order to maintain the pre-treatment blood pressures because the body has reached homeostasis at its abnormally high blood pressure. The blood pressure lowering effect becomes apparent when prazosin is taken for longer periods of time. The heart rate and contractility go back down over time and blood pressure decreases. The antihypertensive characteristics of prazosin make it a second-line choice for the treatment of high blood pressure. Prazosin is also useful in treating urinary hesitancy associated with prostatic hyperplasia, blocking alpha-1 receptors, which control constriction of both the prostate and urethra. Although not a first line choice for either hypertension or prostatic hyperplasia, it is a choice for patients who present with both problems concomitantly. Common (4–10% frequency) side effects of prazosin include dizziness, headache, drowsiness, lack of energy, weakness, palpitations, and nausea. Less frequent (1–4%) side effects include vomiting, diarrhea, constipation, edema, orthostatic hypotension, dyspnea, syncope, vertigo, depression, nervousness, and rash.

CNS Activity

Originator

Approval Year

Targets

Primary Target	Pharmacology	Potency
Adrenergic receptor alpha-1 171 Target ID: CHEMBL2094251 Sources: https://www.ncbi.nlm.nih.gov/pubmed/9135028	Antagonist 2849	2.0 nM [Kd]
Alpha-1a adrenergic receptor 67 Target ID: CHEMBL229 Sources: https://www.ncbi.nlm.nih.gov/pubmed/25557493	Antagonist 2849	0.04 nM [Ki]
Alpha-1b adrenergic receptor 45 Target ID: CHEMBL232 Sources: https://www.ncbi.nlm.nih.gov/pubmed/9888842	Antagonist 2849	0.28 nM [Ki]
Alpha-1d adrenergic receptor 37 Target ID: CHEMBL223 Sources: https://www.ncbi.nlm.nih.gov/pubmed/24365159	Antagonist 2849	0.42 nM [Ki]

Conditions

Condition	Modality	Highest Phase	Product
Hypertension 575 Sources: https://www.accessdata.fda.gov/drugsatfda_docs/label/2015/017442%20s043lbl.pdf	Primary	Approved 8583	MINIPRESS Approved Use Prazosin hydrochloride capsules are indicated in the treatment of hypertension. They can be used alone or in combination with other antihypertensive drugs such as diuretics or beta-adrenergic blocking agents. Launch Date 1976
Prostatic hyperplasia 4 Sources: https://clinicaltrials.gov/ct2/show/NCT00687388	Primary	Phase IV 63	MINIPRESS Approved Use Prazosin hydrochloride capsules are indicated in the treatment of hypertension. They can be used alone or in combination with other antihypertensive drugs such as diuretics or beta-adrenergic blocking agents. Launch Date 1976
Post-traumatic headache 2 Sources: https://clinicaltrials.gov/ct2/show/NCT02965027	Primary	Phase IV 63	MINIPRESS Approved Use Prazosin hydrochloride capsules are indicated in the treatment of hypertension. They can be used alone or in combination with other antihypertensive drugs such as diuretics or beta-adrenergic blocking agents. Launch Date 1976

C_max

Value	Dose	Co-administered	Analyte	Population
40 ng/mL EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/7379445/	20 mg single, oral dose: 20 mg route of administration: Oral experiment type: SINGLE co-administered:		PRAZOSIN plasma	Homo sapiens population: UNHEALTHY age: ADULT sex: FEMALE / MALE food status: UNKNOWN

AUC

Value	Dose	Co-administered	Analyte	Population
281 ng × h/mL EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/7379445/	20 mg single, oral dose: 20 mg route of administration: Oral experiment type: SINGLE co-administered:		PRAZOSIN plasma	Homo sapiens population: UNHEALTHY age: ADULT sex: FEMALE / MALE food status: UNKNOWN

T_1/2

Value	Dose	Co-administered	Analyte	Population
5.8 h EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/7379445/	20 mg single, oral dose: 20 mg route of administration: Oral experiment type: SINGLE co-administered:		PRAZOSIN plasma	Homo sapiens population: UNHEALTHY age: ADULT sex: FEMALE / MALE food status: UNKNOWN

F_unbound

Value	Dose	Co-administered	Analyte	Population
7.5% EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/7379445/	20 mg single, oral dose: 20 mg route of administration: Oral experiment type: SINGLE co-administered:		PRAZOSIN plasma	Homo sapiens population: UNHEALTHY age: ADULT sex: FEMALE / MALE food status: UNKNOWN

Overview

CYP3A4	CYP2C9	CYP2D6	hERG
			inhibitor 2217

OverviewOther

Other Inhibitor	Other Substrate	Other Inducer
OCT3 159 OCT1 620 OCT2 779

Drug as perpetrator

Target	Modality	Activity
OCT1 656	inhibitor 4027 Sources: https://pubmed.ncbi.nlm.nih.gov/19833842/	yes [IC50 1.56 uM]
OCT3 161	inhibitor 4027 Sources: http://www.ncbi.nlm.nih.gov/pubmed/12110607	yes [IC50 12.6 uM]
OCT2 782	inhibitor 4027 Sources: https://pubmed.ncbi.nlm.nih.gov/19833842/	yes [IC50 80.4 uM]

Tox targets

Target	Modality	Activity	Metabolite	Clinical evidence
hERG 2263	inhibitor 2237 Sources: https://pubmed.ncbi.nlm.nih.gov/15098086/

Sourcing

Vendor/Aggregator	ID	URL
ChEBI	CHEBI:8364	https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:8364
eMolecules	670703	https://www.emolecules.com/cgi-bin/more?vid=670703
MolPort	MolPort-000-891-036	https://www.molport.com/shop/molecule-link/MolPort-000-891-036
ZINC	ZINC000095616601	http://zinc15.docking.org/substances/ZINC000095616601

PubMed

Title	Date	PubMed
Phe-308 and Phe-312 in transmembrane domain 7 are major sites of alpha 1-adrenergic receptor antagonist binding. Imidazoline agonists bind like antagonists.	2001-07-06	11331292
Hemorrhage-induced alpha-adrenergic signaling results in myocardial TNF-alpha expression and contractile dysfunction.	2001-07	11406472
Synthesis, biological evaluation, and pharmacophore generation of new pyridazinone derivatives with affinity toward alpha(1)- and alpha(2)-adrenoceptors.	2001-06-21	11405649
In the formalin model of tonic nociceptive pain, 8-OH-DPAT produces 5-HT1A receptor-mediated, behaviorally specific analgesia.	2001-06-08	11399266
Structure-activity studies for a novel series of bicyclic substituted hexahydrobenz[e]isoindole alpha1A adrenoceptor antagonists as potential agents for the symptomatic treatment of benign prostatic hyperplasia.	2001-06-07	11384242
A functional assay for detection of the mitoxantrone resistance protein, MXR (ABCG2).	2001-06-06	11406094
Comparison of prazosin, terazosin and tamsulosin: functional and binding studies in isolated prostatic and vascular human tissues.	2001-06-01	11398170
alpha-1 and alpha-2 Adrenergic antagonists relieve thermal hyperalgesia in experimental mononeuropathy from chronic constriction injury.	2001-06	11375846
Vascular actions of MDMA involve alpha1 and alpha2-adrenoceptors in the anaesthetized rat.	2001-06	11375260
Noradrenaline modulates oyster hemocyte phagocytosis via a beta-adrenergic receptor-cAMP signaling pathway.	2001-06	11356037
Interaction of formamidine pesticides with the presynaptic alpha(2)-adrenoceptor regulating.	2001-05-01	11312645
Role of G(i)-proteins in norepinephrine-mediated vasoconstriction in rat tail artery smooth muscle.	2001-05-01	11301051
Initiation of nonselective alpha1-antagonist therapy and occurrence of hypotension-related adverse events among men with benign prostatic hyperplasia: a retrospective cohort study.	2001-05	11394731
Evaluating adverse cardiovascular effects of drug treatment for benign prostatic hyperplasia (BPH): methodological considerations.	2001-05	11337216
Identification and localization of three photobinding sites of iodoarylazidoprazosin in hamster P-glycoprotein.	2001-05	11322883
Structure-hepatic disposition relationships for cationic drugs in isolated perfused rat livers: transmembrane exchange and cytoplasmic binding process.	2001-05	11303070
Noradrenaline modulates hemocyte reactive oxygen species production via beta-adrenergic receptors in the oyster Crassostrea gigas.	2001-05	11246068
The noradrenaline-dopamine interaction in the rat medial prefrontal cortex studied by multi-probe microdialysis.	2001-04-27	11343687
beta-Adrenergic stimulation synchronizes intracellular Ca(2+) release during excitation-contraction coupling in cardiac myocytes.	2001-04-27	11325871
5-HT1A and 5-HT2 receptors differentially regulate the excitability of 5-HT-containing neurones of the guinea pig dorsal raphe nucleus in vitro.	2001-04-27	11311877
A61603-induced vasoconstriction in porcine carotid vasculature: involvement of a non-adrenergic mechanism.	2001-04-13	11334851
Cis- and trans-N-benzyl-octahydrobenzo[g]quinolines. Adrenergic and dopaminergic activity studies.	2001-04-09	11294383
Call for global snake-bite control and procurement funding.	2001-04-07	11303612
Role of the alpha(1)- and alpha(2)-adrenoceptors of the paraventricular nucleus on the water and salt intake, renal excretion, and arterial pressure induced by angiotensin II injection into the medial septal area.	2001-04	11403985
Expression and functional characterization of the mt1 melatonin receptor from rat brain in Xenopus oocytes: evidence for coupling to the phosphoinositol pathway.	2001-04	11316324
Hemodynamic effects of a combination of prazosin and terlipressin in patients with viral cirrhosis.	2001-04	11316172
Effect of alpha-adrenoceptor agents on imipramine-induced antinociception in nerve-ligated mice.	2001-04	11313154
The short-term effects of terazosin in Japanese men with benign prostatic hyperplasia.	2001-04	11301364
Effect of the blood substitute diaspirin crosslinked hemoglobin in rat mesenteric and human radial collateral arteries.	2001-04	11300652
MEK1/2-ERK1/2 mediates alpha1-adrenergic receptor-stimulated hypertrophy in adult rat ventricular myocytes.	2001-04	11273730
Effect of KMD-3213, an alpha1A-adrenoceptor antagonist, on the prostatic urethral pressure and blood pressure in male decerebrate dogs.	2001-04	11260350
Determinants of terminal mesenteric artery resistance during the first postnatal month.	2001-04	11254494
Posttraining infusion of norepinephrine and corticotropin releasing factor into the bed nucleus of the stria terminalis enhanced retention in an inhibitory avoidance task.	2001-03-31	11403518
Effect of JTH-601, a putative alpha(1L)-adrenoceptor antagonist, on guinea pig nasal mucosa vasculature.	2001-03-23	11282123
Modulation of MK-801-induced behaviour by noradrenergic agents in mice.	2001-03-01	11314680
Enduring vulnerability to transient reinstatement of hemiplegia by prazosin after traumatic brain injury.	2001-03	11284550
Characterization of [3H]CGP 12177 binding to beta-adrenergic receptors in intact eel hepatocytes.	2001-03	11254364
Morphological and functional in vitro and in vivo characterization of the mouse corpus cavernosum.	2001-03	11250885
The role of several alpha(1)- and alpha(2)-adrenoceptor subtypes mediating vasoconstriction in the canine external carotid circulation.	2001-03	11250880
Nerve evoked P2X receptor contractions of rat mesenteric arteries; dependence on vessel size and lack of role of L-type calcium channels and calcium induced calcium release.	2001-03	11250870
Neural mechanisms involved in the delay of gastric emptying and gastrointestinal transit of liquid after thoracic spinal cord transection in awake rats.	2001-02-20	11280307
Chronic vasodilation induces matrix metalloproteinase 9 (MMP-9) expression during microvascular remodeling in rat skeletal muscle.	2001-02	11296850
[A randomized comparative study assessing once versus twice a day treatment of benign prostatic hyperplasia with terazosin].	2001-02	11280890
Effects of losartan, prazosin and a vasopressin V1-receptor antagonist on renal and femoral blood flow in conscious sheep.	2001-01	11350268
Enhancer aided in vitro permeation of atenolol and prazosin hydrochloride through mice skin.	2001-01	11349525
Vasoconstrictive drugs increase carbonic anhydrase I in vascular smooth muscle while vasodilating drugs reduce the activity of this isozyme by a direct mechanism of action.	2001	11392054
Accurate mass measurement of synthetic analogues of prazosine by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry.	2001	11319786
Diabetes-induced changes in retinal NAD-redox status: pharmacological modulation and implications for pathogenesis of diabetic retinopathy.	2001	11287819
Hypoxic-ischaemic brain damage in immature rats: effects of adrenoceptor modulation.	2001	11277361
Lower urinary tract symptoms suggestive of benign prostatic obstruction--Triumph: the role of general practice databases.	2001	11275742

Patents

Sample Use Guides

In Vivo Use Guide

Initial: 1 mg PO q8-12hr Maintenance: 6-15 mg/day divided 2 or 3 times daily; alternatively, 1-5 mg PO BID; may increase dose to 20 mg/day in divided doses; some patients may benefit from up to 40 mg/day in divided doses

Route of Administration: Oral

In Vitro Use Guide

Both HEL and K562 cells, with a start cell number of 1×E4 cells/ml, were incubated in 24-well plates 2 or 3 days with different concentrations of the receptor subtype-specific adrenergic antagonists, prazosin in triplicates. All antagonists were obtained from Sigma Austria and were added to the culture medium dissolved in Aqua bidest. After the incubation period, proliferation and viability of the cells were measured with a CASY-1® Cell Counter and Analyzer (Schaerfe, Reutlingen, Germany).

Substance Class	Chemical Created by `admin` on `Mon Mar 31 17:51:55 GMT 2025` Edited by `admin` on `Mon Mar 31 17:51:55 GMT 2025`
Record UNII	XM03YJ541D
Record Status	`Validated (UNII)`
Record Version

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Name

Type

Language

PRAZOSIN

Official Name

English

CP-122991

Preferred Name

English

prazosin [INN]

Common Name

English

1-(4-AMINO-6,7-DIMETHOXYQUINAZOLIN-2-YL)-4-(FURAN-2-YLCARBONYL)PIPERAZINE

Systematic Name

English

TERAZOSIN HYDROCHLORIDE DIHYDRATE IMPURITY K [EP IMPURITY]

Common Name

English

PRAZOSIN [VANDF]

Common Name

English

PRAZOSIN [MI]

Common Name

English

Prazosin [WHO-DD]

Common Name

English

Classification Tree Code System Code

NCI_THESAURUS

C29713